WC II .25 POI Changes

My wildcat does the same thing. It has a large extreme spread. I only pest and plink so it doesn’t bug me a lot. Best bet is to switch to a Huma in my opinion. I attached my results below and this is after getting my rifle back back from FX before I was getting 50+ FPS in extreme spread. 




View attachment 1560985289_724596905d0abec93a8dc2.84836563_Fx Wildcat .numbers

So subtract out the regulator for just a moment: we shot airguns for years, decades even, without any regulator at all. How? Hammer tension balanced against the valve opening force meant that you could endure a substantial variation in pressure, 100 bar in some cases, and see an extreme spread not dramatically larger than yours. So, for that reason, I'm a bit skeptical that it is the reg. That doesn't mean it isn't, but I feel like all too often a member here has a velocity consistency issue and people start chanting "Huma." Thing is, if it isn't the reg, you just burned a fair bit of money for no reason and are no closer to the solution. 

And this is an important takeaway: if your gun is tuned right, your reg can actually permit pretty substantial pressure variations and you won't see a large ES. And despite the odd complaint on the forum here, FXs actually tend to come in a fairly high state of tune.



So on an FX Wildcat, just below the edge of the stock on the left hand side of the action, you should be able to see a brass (pretty sure it is brass) grub screw threaded into the side of the action. That is your reg pressure testing port. You can, fairly easily, get a gauge and install it there. A corresponding groove will need to be cut in your stock if you want to keep it, but if you think it is your reg or you just want to fettle your Wildcat a bit, that is a pretty easy and inexpensive thing to invest in to find out. 

Other things which can cause inconsistency though are things like the cleanliness of the barrel, lubricant in your air supply (both mucking with the reg and spraying down the barrel), the pellets themselves, or lubricant on your hammer. And one other thing people rarely think to check is the chrono itself. Chronos, for a variety of different reasons, can give inconsistent results. Before you tear your hair out messing with the gun, it is worth just doing some math to see what sort of vertical string you'd expect with that kind of velocity variation. Then go shoot groups and see if that is what you observe. A 50fps ES should result in pretty substantial vertical stringing. 

I feel like my wings have been clipped a little bit here, as I'd like to share links for all of this and can't (the forum will delete your post when you try to submit it if your posts contains links), however both the search bar and google search are a powerful tool to dive deeper into all these things. In general though, when troubleshooting, I try to check the easiest and least expensive things first. So that'd be shooting some groups/doing some math and seeing what kind of vertical spread you get. Then sorting pellets for mass and head size and seeing if that fixes it. Then cleaning your hammer/hammer guide and your barrel. Then tuning your HST to be right off the edge of the performance "knee." Then testing your reg for pressure consistency (ordering a gauge). If all that doesn't work, and excluding the gauge part it should only take an afternoon to check, you should have a pretty darn good idea whether or not the reg has a consistency issue. If it does, I personally would just take a look at my existing reg before buying a replacement, but if you didn't want to do that the Huma is a well respected replacement option. 


I hope that was helpful. I realize I just threw a lot at you without any citation at all so take it with a generous spoonful of salt, but I hope it provides some insight none the less. 

My Gen 1 Wildcat was doing the same thing with an ES of about 50 fps and grouping about 3 1/2". It was still under warranty so I sent it into Ernest at FX and he replaced the A-9 o ring that seals the back side of the valve stem. When he told me it wasn't the regulator I thought he was pissing down my back and telling me it was raining … but he sent it back to me along with his test shots. I went upstairs and sighted in on my 70 yard targets ( 1" circles ) and not one pellet from that magazine even touched the lines on the outside of the ring. They were all in a cluster measuring about a half inch. Just an o-ring!

Great read STO could you explain the performance knee and how to tune? Thank you.

What pellet? Is there major accuracy issues? Do you have a moderator on it? Have you checked your probe O ring? Just the usual questions, also both of mine will do this at certain hammer settings, especially if it’s on the hot side? When you say clean, does that mean hammer removal? And possibly lube? Some people do it, just asking. Also, are you taking this data at different times? Like 30 min or more apart between groups? Because the stock reg will creep and give you crazy low first and possibly second shot? Then 2or 3 st dev after that. Just what mine do?

I would follow STO`s advise. If you remove the stock, and attach an accurate gauge (borrow one maybe?) you can dryfire the gun, and see if the pressure remains the same after each shot. If it doeas there is probably nothing wrong with the reg.

that spread is too wide.... i think you have to check regulator and breech orings!!

well i for one am chanting HUMA

2 wildcats. spreads in the 20s, huma 10-12

well i for one am chanting HUMA

2 wildcats. spreads in the 20s, huma 10-12

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I hate to step on your toes, but that suggests to me there is still something wrong with your gun. You should be single digits methinks. :/ (sorry) 

Great read STO could you explain the performance knee and how to tune? Thank you.

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My wings have been clipped, I can't post links however there are a lot of great guides on this forum. You may then want to spend a little time searching around the forum for a better guide than I'm about to type out here, if for no other reason than I'm just some random crazy dude on the internet. Also that valve o-ring likkitysplyt mentioned is worth checking/replacing with higher duro. That could also very easily, maybe even very likely, be it. 

So how to tune for the performance knee. (and anyone please jump in and correct me if you've got a better strategy) So start with your HST (hammer spring tension) low, and start shooting over the chrono slowly increasing the HST and watching your FPS rise. Eventually with more and more tension, your FPS for a given pellet will plateau and then begin to go down because you're actually hitting the valve too hard. The "knee" is this performance plateau. You want your HST set at the very edge of the lower-tension side of it, so you're probably going to have to go up and down a time or two to find that sweet spot. This optimizes your air efficiency, minimizes pellet disruption at the muzzle (less muzzle blast), and critically in this case means that if your plenum pressure fluctuates up or down you're not going to see huge FPS swings. Also, with the WC, be sure to loctite your HST adjust when you're done, as they have a tendency to move. 

I hope all that made sense. You'll see people like Ted Bier with these long videos talking about "harmony." What they're talking about, in essence, is finding the optimum velocity for a given pellet and barrel, and then tuning your reg and HST so that you shoot those pellets at that velocity with your reg set so your HST is at said "knee." Basically optimizing all parameters simultaneously with each other. This, in my humble opinion, is why guns like the Impact and Crown have dual gauges, externally adjustable regs, and externally adjustable HSTs, it isn't to dial your power up and down in the field, that is what the power wheel is for, it is to make tuning your gun in your workshop super-duper convenient. It also should be noted that FX guns tend to come on/near said sweet spot, or "in harmony" for a specific pellet. It can change a bit as things break in, but generally speaking you should be starting fairly close. 

I hope that is helpful, and factually accurate. And please don't take my word for everything, I'm just some crazy dude on the internet and this is just one possibility of many regarding why your gun's ES isn't what it should be. 

Could also be he simply need to shoot 2000 more shots?

Here are my numbers with in .25 with 25.39 and 33.95 JSB pellets. No regulator adjustment only hammer. Both down to about 150 bar

It takes more FPS variation than most people want to admit, to really make a difference on target even at 50y for an otherwise hardhitting rifle. Those spreads in a 12fpe .177 would have been all over the target. BUT the spreads you just posted would be crazy even for an unregulated gun from a decade (or more) ago....especially within a mag's shots. My bet - Your hammer spring is not adjusted as well as it was in the first chrony results you posted higher up the page. And, it may be moving, even shot by shot. That's all I can think of. With those spreads I don't think you can begin to evaluate the function of the regulator.

Last note, my Wildcats' hammer spring tension have a very narrow range within which they adjust as expected. Then they (many) need to locked in place.